The present invention relates to a radio communication apparatus with a hands-free communication capability for allowing the user of the apparatus to converse without holding it by hand and, more particularly, to a hands-free radio communication apparatus applicable to a motor vehicle.
Today, persons driving motor vehicles while speaking on portable telephones are not rare. However, driving a motor vehicle with one hand while holding a handset with the other hand is not desirable from the safety standpoint. Some different measures have been proposed against such a dangerous situation and include a portable telephone having a hands-free communication capability. A hands-free portable telephone allows a person to converse without holding a handset, i.e., while holding a steering wheel with both hands.
On-board portable telephones with a hands-free communication capability are disclosed in, e.g., Japanese Patent Laid-Open Publication No. 4-368246 and Japanese Utility Model Laid-Open Publication No. 5-20450. A problem with the conventional hands-free portable telephones including ones taught in the above documents is that at the time of a call incoming, the operator of a motor vehicle must press some button to answer the call while steering the vehicle with one hand at great risk. Another problem is that the hands-free feature is not achievable without arranging some extra parts in a passenger compartment beforehand. In addition, such extra parts arranged in the limited space of a passenger compartment would obstruct the operator's steering operation.
Technologies relating to the present invention are also disclosed in, e.g., Japanese Patent Laid-Open Publication Nos. 62-43941, 62-287730, 3-198540, 4-246925, 5-105005, 7-250144, and 8-46678.